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Like David said, the comments might not be needed. Thanks. >> >> I like the comments! They may be uninteresting to those who are >> already familiar with these things, but they aren't the target audience. >> >> How are others to become familiar, if not by this? > > I mean, it's one of the basic rules: if you lookup a page in the page table, the > moment you drop the lock that might be invalid. > > If we were to document that everywhere... this is not really the secret sauce we > want to document everywhere. In this particular case, split_folio() is used in migrate_vma_split_folio() and split_folio() wraps __split_huge_page_to_list_to_order(), which documents the requirement of elevated folio reference. One who wants to get familiar with kernel code can be expected to chase down to __split_huge_page_to_list_to_order() and find the requirement. With LLMs, it is probably as easy as asking “why is folio_get() needed here?”. Best Regards, Yan, Zi